In a certain store, cashiers can serve $55$ customers per hour on average. If $x$ customers arrive at the store in a given hour, then the average number of customers $C$ waiting in line can be modeled by the function where $x<55$. Answer the following questions with a graphing calculator. Round your answers to integers. 1) If $50$ customers arrived in the store in the past hour, there are approximately customers waiting in line. 2) If there are $3$ customers waiting in line, approximately customers arrived in the past hour.